1. Field of the Invention
The invention relates to a suction jet pump having a propellant line, a propulsion jet nozzle, a suction region, a mixing pipe, and a diffuser, wherein the propulsion jet nozzle and the mixing pipe are orientated in a linear manner with respect to each other.
2. Detailed Description of Prior Art
Suction jet pumps are known and are used to convey fluids and gases, wherein the main advantage thereof is that they do not require any electromotive drive, but are instead driven by a propellant supplied by a propellant line. For this reason, they are used in motor vehicles to convey fuel in the fuel container in that they are used to redistribute the fuel in the fuel container or to fill surge tanks of conveyor units. The suction jet pumps are in this instance generally driven by a fuel pump by a portion of the conveying quantity of the fuel pump being branched off and being used to drive the suction jet pump. The disadvantage of suction jet pumps is their relatively low degree of efficiency. For this reason, the sizing of the individual components of the suction jet pump has particular significance in order to achieve the greatest possible conveying power. In particular the length of the individual components is decisive in this instance. With an in-line arrangement of the suction jet pump, however, lengths are thereby very quickly reached at which suction jet pumps can no longer be assembled in fuel containers.
It is known to shorten the length of the suction jet pump by angling the propellant line directly upstream of the propulsion jet nozzle through 180° so that the propellant line extends parallel with the remaining suction jet pump having a propulsion jet nozzle, suction region, mixing pipe and diffuser. Yet another shortening of the length of the suction jet pump can be achieved by the cross section of the nozzle being increased. With the propulsion quantity thereby increased and consequently associated increase of the drive power, shortened lengths of the components of the suction jet pump can be compensated for. Since the drive quantity branched off from the fuel pump for the suction jet pump is substantially proportional to the total delivery quantity of the fuel pump, the use of fuel pumps controlled in accordance with requirements has the disadvantage that, in travel situations with low fuel consumption, the propulsion quantity branched off for the suction jet pump approaches zero, which has a negative effect on the degree of efficiency of the suction jet pump. In this regard, with fuel pumps controlled in accordance with requirements, the shortened lengths of the components of the suction jet pump cannot be compensated for by an increased propulsion quantity.